// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/output/overlay_strategy_underlay.h"

#include "cc/output/overlay_candidate_validator.h"
#include "cc/quads/draw_quad.h"
#include "cc/quads/solid_color_draw_quad.h"

namespace cc {

OverlayStrategyUnderlay::OverlayStrategyUnderlay(
    OverlayCandidateValidator* capability_checker)
    : capability_checker_(capability_checker)
{
    DCHECK(capability_checker);
}

OverlayStrategyUnderlay::~OverlayStrategyUnderlay() { }

bool OverlayStrategyUnderlay::Attempt(ResourceProvider* resource_provider,
    RenderPass* render_pass,
    OverlayCandidateList* candidate_list)
{
    QuadList& quad_list = render_pass->quad_list;
    for (auto it = quad_list.begin(); it != quad_list.end(); ++it) {
        OverlayCandidate candidate;
        if (!OverlayCandidate::FromDrawQuad(resource_provider, *it, &candidate))
            continue;

        // Add the overlay.
        OverlayCandidateList new_candidate_list = *candidate_list;
        new_candidate_list.push_back(candidate);
        new_candidate_list.back().plane_z_order = -1;

        // Check for support.
        capability_checker_->CheckOverlaySupport(&new_candidate_list);

        // If the candidate can be handled by an overlay, create a pass for it. We
        // need to switch out the video quad with a black transparent one.
        if (new_candidate_list.back().overlay_handled) {
            new_candidate_list.back().is_unoccluded = !OverlayCandidate::IsOccluded(candidate, quad_list.cbegin(), it);
            const SharedQuadState* shared_quad_state = it->shared_quad_state;
            gfx::Rect rect = it->visible_rect;
            SolidColorDrawQuad* replacement = quad_list.ReplaceExistingElement<SolidColorDrawQuad>(it);
            replacement->SetAll(shared_quad_state, rect, rect, rect, false,
                SK_ColorTRANSPARENT, true);
            candidate_list->swap(new_candidate_list);

            // This quad will be promoted.  We clear the promotable hints here, since
            // we can only promote a single quad.  Otherwise, somebody might try to
            // back one of the promotable quads with a SurfaceView, and either it or
            // |candidate| would have to fall back to a texture.
            candidate_list->promotion_hint_info_map_.clear();
            candidate_list->AddPromotionHint(candidate);
            return true;
        } else {
            // If |candidate| should get a promotion hint, then rememeber that now.
            candidate_list->promotion_hint_info_map_.insert(
                new_candidate_list.promotion_hint_info_map_.begin(),
                new_candidate_list.promotion_hint_info_map_.end());
        }
    }

    return false;
}

} // namespace cc
